The invention relates to a vehicle seat adjustment device and particularly to a device for selectively changing the inclination of a vehicle seat backrest or the comfort position of an armrest, headrest, or other support member of a vehicle seat.
A known adjusting device includes a hand wheel which is mounted on a first fitting part, the rotary movements of which are transmitted on the power take-off side via an intermediate gear stage to a further gear mounted on the first fitting part. In the transmission path, there is a braking device which allows the rotary movement emanating from the hand wheel to be transmitted to a second fitting part articulated to the first fitting Part, but which produces a locking effect when force is introduced in reverse.
An adjusting device of the type described above is known, in principle, from German Unexamined Published Patent Application No. 2,905,334. The braking device is assigned to the hand wheel in order to provide the adjusting device on a production vehicle. Although the hand wheel is moved into an easily accessible region, nevertheless only a single adjusting device can be actuated via the hand wheel as a result of this known arrangement.
According to the present invention, an apparatus is provided for adjusting a vehicle seat having a movable support member. The apparatus includes a first frame member and a second fame member pivotably articulated to the first frame member. A backrest is desirably mounted on the second frame member. First and second driven gears are rotatably mounted on the first frame member.
The apparatus further includes first transmission means for pivoting the second frame member in relation to the first frame member to change the inclination of the second frame member and second transmission means for changing the position of the movable support member in relation to the second frame member. The first transmission means is activated in response to rotation of the first driven gear and the second transmission means is activated in response to rotation of the second driven year. Control means is provided for selectively engaging either the first driven gear to activate the first transmission means or the second driven gear to activate the second transmission means. The control means is movable in relation to the first frame member to a first position to engage the first driven gear and to a second position to engage the second driven gear. The control means includes a shaft mounted on the first frame member for rotation about an axis and for movement along said axis. A driving gear is fixed to one end of the shaft for selective engagement of the first or second driven gears. A hand wheel is fixed to the other end of shaft for imparting rotation to driving gear to rotate the selected driven gear.
In addition, first brake means is provided for preventing rotation of the first driven gear in at least one direction when the first driven gear and the driving gear are disengaged.
Second brake means is also provided for preventing rotation of the second driven gear in at least one direction when the second driven gear and the driving gear are disengaged. In operation, the control means is selectively movable by an operator to its first position to permit the operator to rotate the hand wheel to activate the first transmission means thereby changing the inclination of the second frame member or to its second position to permit the operator to rotate the hand wheel to activate the second transmission means thereby changing the position of the movable support member.
One object of the present invention is to redesign the known device in such a way that the adjusting movement of the hand wheel can be imparted so a further adjustable device (e.g. armrest or headrest) bearing no functional relationship to the backrest inclination adjustment, while at the same time ensuring that the position of the particular device not actuated by the hand wheel cannot change automatically.
This object is achieved, in part, because the second brake means of the intermediate gear stag is assigned to a first transmission path, because the hand wheel is displaceable in the axial direction, and because the driving gear on the power take-off side can be engaged selectively with the first driven gear or with a second gear which is located in a second transmission path. The rotary movement of the second driven gear is transmitted, with the first brake means being interposed, to a built-on or built-in part assigned to the backrest, such as a head or armrest, for the purpose of adjusting the latter.
Although it is known per se from German Utility Model No. 7,521,032, on a vehicle seat, to engage the gear on the power take-off side selectively with two different gears as a result of displacement of a hand wheel in the axial direction, nevertheless here the gears are arranged axially in series and are in a direct functional relationship with one another. Furthermore, a spindle drive is inserted as a brake in each transmission path, thus resulting in a high transmission ratio unsuitable for rapid adjustment.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawing which shows, for purpose of illustration only, an embodiment in accordance with the present invention.